Public Law analysis: The Grand Chamber of the Court of Justice ruled, following a preliminary reference from the Supreme Court of Ireland, on the role of an EU Member State court in executing an arrest warrant from the UK. The Court of Justice remarked on the nature of the EU-UK relationship post-Brexit, as well as the obligation on EU Member State authorities of independently verifying compliance with the EU Charter of Fundamental Rights (the ‘Charter’), even when the equivalent ECHR right has been deemed not breached. The Court of Justice held that the EU Member State court must independently examine the risk of breach of the Charter before deciding on execution of the arrest warrant, even where the matter has been determined to not be in breach of Article 7 ECHR; which may involve requesting additional information and guarantees from the issuing judicial authority, as well as objective, reliable, specific and updated information, and should refuse such a request where it has a real risk of change to the actual scope of the penalty, which would go against the principle of legality. Written by William Moody, barrister at Henderson Chambers.